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How to Get Rid of Hair Algae in Fish Tank? 



How to Get Rid of Hair Algae in Fish Tank

In a nutshell, the key to getting rid of hair algae in your fish tank lies in maintaining balanced nutrient levels and optimizing environmental factors, such as water quality, flow, and light levels. Once these are adequate for the needs of your aquarium, if you want a less hands-on approach and want more diversity in your aquarium, introducing algae-eating species can help control hair algae growth. In severe cases where other approaches fail, chemical treatment may be considered.

Keep on reading to discover what causes hair algae and why hair algae is growing in your aquarium, as well as the best methods to deal with it depending on your setup! 


If you are a passionate aquarium owner, it’s likely that the mere thought of unsightly hair algae infiltrating your beautiful underwater world can make you break out in a cold sweat. We understand your dedication to creating a captivating and harmonious environment for your aquatic companions.  

Hair algae can be a persistent and frustrating issue, regardless of whether you have a saltwater tank, a freshwater tank, a reef tank, or a carefully curated planted tank.

Its rapid growth and tenacity can quickly overshadow the vibrant colors of your fish and your carefully chosen plants, hampering the overall aesthetics of your aquarium.

Moreover, they can clog filters, hinder circulation and mess up the oxygen levels, endangering the health of your fish. But fear not! In this comprehensive blog post, we will equip you with the knowledge and strategies to eradicate hair algae, allowing your aquatic haven to flourish. 

Throughout this article, we will explore the underlying causes of hair algae growth, guiding you through a range of effective methods tailored to different types of tanks. Whether you’re dealing with hair algae in a saltwater oasis, a freshwater haven, a delicate reef environment, or a lush planted tank, we’ve got you covered.  

What is hair algae? 

Image source – Healthy ponds

Hair algae, also known as filamentous algae, is a type of algae that forms long, thread-like strands. It can be green, brown, or black in color and has a wiry appearance, resembling strands of hair.

Hair algae growth is typically triggered by a combination of factors, including imbalanced nutrient levels, excessive light, poor water quality, and inadequate water flow. 

What Causes Hair Algae in Aquarium? 

The primary cause of hair algae growth is an imbalance in nutrient levels, particularly high levels of nitrates and phosphates in the water. These nutrients act as fuel for algae growth, providing an abundant food source for hair algae to thrive. Overfeeding, decaying organic matter, and insufficient water changes can contribute to elevated nutrient levels in the aquarium. 

  • Excessive light exposure is another contributing factor. Hair algae thrives in areas where light is abundant, and excessive or prolonged lighting periods can stimulate its growth. This is particularly true if the tank’s lighting is not properly balanced or if there is inadequate shading or intensity control. 
  • Poor water quality, including high levels of ammonia and nitrites, can also create favorable conditions for hair algae growth. These pollutants can result from overstocking, overfeeding, or inadequate filtration and water maintenance practices. 
  • Inadequate water flow and stagnant areas within the aquarium can create localized environments that are ideal for hair algae to settle and proliferate. Insufficient water circulation can lead to the accumulation of nutrients and organic debris, creating a breeding ground for algae growth. 

What harm does hair algae do? 

If you are a new newbie aquarist, you might be wondering why does any of this matter – it’s just algae, right? While hair algae may seem harmless at first glance, its presence can have several negative impacts on your aquarium ecosystem.

Firstly, hair algae can overshadow the aesthetic beauty of your tank, obstructing the view of your fish and plants. This can diminish the overall visual appeal of your aquarium setup. 

Furthermore, hair algae can hinder the growth and health of your aquatic plants. It competes with plants for essential nutrients, light, and space, potentially depriving them of the resources they need to thrive. This can lead to stunted plant growth, reduced oxygen production, and a less vibrant and flourishing aquatic environment. 

In addition to its visual and plant-related consequences, hair algae can also interfere with the overall balance of your aquarium. Excessive growth of hair algae can disrupt water flow, clog filters, and reduce oxygen levels.

This can negatively impact the well-being of your fish and other aquatic inhabitants, as well as the stability of the ecosystem as a whole. 

How to Remove Hair Algae?

While each aquarium is unique, there are general strategies you can employ to effectively remove hair algae. By following these steps, you can combat hair algae and maintain a healthy aquatic environment: 

1. Identify the type of algae 

By knowing what you’re dealing with, you’ll get the best idea of what the root of the problem is and how to move forward.  

In freshwater aquariums, common types of hair algae include various species of filamentous algae, such as Spirogyra, Cladophora, and Oedogonium. These algae typically appear as long, stringy strands or tufts.

filamentous algae
Image source – Parklink

The first signs will be slight green or brown discoloration on surfaces such as rocks, decorations, and plant leaves. As the hair algae proliferates, it can form dense mats or cover large areas in the aquarium, giving the impression of an untidy and unkempt environment.  

Saltwater aquariums share some species with their freshwater counterparts, particularly green hair algae (Cladophora sp.) and filamentous hair algae (Oedogonium sp.). However, there may be additional types of hair algae specific to saltwater environments, especially species of the genus Derbesia

2. Ensuring water quality 

Ensuring water quality 

Ensuring water quality is essential for preventing hair algae growth in your aquarium. All species of hair algae thrive in environments with excessive nutrients, so it’s crucial to monitor the levels of nitrates and phosphates in your tank.

If these levels are higher than recommended, adjustments can be made by reducing the amount and frequency of feeding and implementing a balanced fertilizer regimen tailored to your tank’s specific needs. By maintaining optimal nutrient levels, you can create an environment less conducive to hair algae growth. 

In freshwater aquariums, monitor parameters such as temperature, hardness, ammonia, and other factors to ensure they are within appropriate ranges. Imbalances in these parameters not only provide a favorable environment for hair algae to thrive but can also lead to stress, disease, or even death for your fish. Keeping a careful eye on these variables will help prevent the establishment and spread of hair algae in your freshwater aquarium. 

For saltwater aquariums, in addition to the general water quality considerations, salinity management and the presence of trace elements are crucial factors to watch out for. Maintaining proper salinity levels is essential, and regular testing should be performed to ensure they are within the appropriate range for the species in your tank. Monitoring and supplementing trace elements, such as calcium and magnesium, can also contribute to a healthy marine environment and help prevent conditions favorable for hair algae growth. 

3. Optimize lighting 

Optimizing lighting conditions is another important aspect of preventing hair algae growth. Evaluate the duration and intensity of lighting in your aquarium. Excessive lighting can contribute to the proliferation of hair algae, so it’s crucial to strike a balance. 

First, assess the duration of lighting. Ensure that the photoperiod, or the period of time your aquarium lights are turned on, is appropriate for the needs of your tank inhabitants. Different species of fish, plants, and corals have varying light requirements, so research their specific lighting needs and adjust accordingly. Avoid prolonged lighting periods that can create an excessive amount of available energy for hair algae to thrive. 

Next, consider the intensity of your aquarium lighting. If you’re using artificial lighting, assess whether it’s providing the appropriate intensity for your tank. Too much light can fuel hair algae growth, so it may be necessary to dim the lights or adjust their positioning to reduce the intensity. Opting for LED lights that offer customizable intensity settings can provide greater control over the lighting conditions in your aquarium. 

I personally recommend using a timer to automate your lighting schedule. It not only ensures consistent and regular lighting periods, but also makes it much less of a hassle. 

4. Enhance Water Circulation 

Stagnant water is a breeding ground for hair algae. By increasing water flow and circulation, you can disrupt the settling and growth of hair algae. The improved water movement helps prevent stagnant areas where hair algae can establish and reduces the availability of nutrients that promote its growth. 

In both freshwater and saltwater aquariums, the use of powerheads, wavemakers, or other water circulation devices can be employed to enhance water movement. By creating currents and maintaining consistent flow patterns, these devices help distribute nutrients more evenly throughout the tank, limiting the buildup of excessive nutrients that support hair algae growth. 

Protein skimmers can also be a great help. They work by introducing air bubbles into the water, which attract and remove organic compounds and excess nutrients that can contribute to hair algae growth. By effectively removing these substances, protein skimmers contribute to maintaining optimal water quality and reducing the availability of nutrients for hair algae. 

5. Consider Aquatic Plants 

Whether you have a freshwater planted aquarium or a saltwater reef setup, incorporating aquatic plants or suitable macroalgae can contribute to the overall balance and health of your aquarium ecosystem while enhancing the overall aesthetics. By providing competition for nutrients and creating a more natural environment, plants play a significant role in controlling hair algae growth. 

However, it’s important to ensure that aquatic plants receive adequate lighting, nutrient supplementation, and carbon dioxide supplementation (if needed) to thrive. Finding the right balance is key, as excessive fertilization can actually contribute to algae problems. 

Some popular choices for freshwater species include fast-growing stem plants like Hornwort (Ceratophyllum demersum) and Water Wisteria (Hygrophila difformis), which can outcompete algae for nutrients. Floating plants like Water Lettuce (Pistia stratiotes) and Duckweed (Lemna minor) can also help shade the water surface, reducing light penetration and suppressing algae growth. Pick depending on the desired aesthetic, but also make sure to choose plants that are compatible with your aquarium’s lighting and nutrient levels. 

In saltwater aquariums, incorporating macroalgae can be an effective means of controlling algae. Species such as Chaetomorpha, Caulerpa, and Gracilaria are commonly used for their ability to absorb excess nutrients, including nitrates and phosphates, which can help prevent algae overgrowth. Macroalgae also provide additional benefits by creating natural habitats for microorganisms and serving as a food source for herbivorous fish and invertebrates. 

6. Introduce Algae Eaters 

Incorporating algae-eating species into your freshwater aquarium can aid in controlling algae growth while adding to the biodiversity of your tank. Certain fish species, such as Siamese Algae Eaters, have a voracious appetite for different types of algae, including green spot algae and brush algae. Nerite snails and freshwater shrimp, like Amano shrimp or Cherry shrimp are also known algae aficionados

Likewise, many saltwater species will be more than happy to take care of your hair algae problem. Tangs like the Yellow Tang and Sailfin Tang, as well as blennies such as the Lawnmower Blenny, are excellent choices. You could also consider incorporating hermit crabs into your tank, as they are natural grazers that consume hair algae. 

7. Manual removal 

You can always take a hands-on approach to remove hair algae from your tank. Gently scrub affected areas using a toothbrush or by hand. Focus on target areas where hair algae growth is prominent. Be careful not to damage delicate plants or corals during the removal process. If you fixed the root cause of the issue, such as balancing nutrient levels, hair algae shouldn’t be a problem again. 

8. Use Algae Control Products 

If all the other methods fail to address the hair algae problem, resorting to reef-safe algae control products designed specifically for aquarium use can be a viable option. These products should not harm your fish or other marine life as long as you carefully follow the instructions provided. 


Hair algae can be an unwelcome presence in fish tanks, but with the right approach, you can successfully combat and prevent its growth. By addressing nutrient imbalances, enhancing water flow, introducing algae-eating organisms, and practicing regular maintenance, you can maintain a healthy and vibrant aquarium environment. Remember to tailor your approach based on the specific requirements of saltwater tanks, freshwater tanks, reef tanks, and planted tanks. With consistency and diligence, you can enjoy an algae-free tank that showcases the beauty of your aquatic life. 

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